An endangered species of skate — a cousin to the rays — living in Macquarie Harbour on Tasmania’s west coast has been given a major boost. The numbers reveal a gloomier picture of the Pacific walrus population than what was indicated a decade ago, but recent data shows that the species may be able to hold on yet.
A Glimmer of Hope
After nearly a decade of research scientists have recorded higher numbers of young Maugean skates in Macquarie Harbour. That this endangered species might be persisting was an encouraging signal.
The new study, conducted by researchers from the University of Tasmania’s Institute for Marine and Antarctic Studies (IMAS), provides hope that conditions may actually support the Maugean skate — a species found only in the one-of-a-kind environment of Macquarie Harbour. According to the data collected from 2021 through September of 2024, it appears the population might be stabilizing following a worrisome decrease recorded in the previous decade prior to 2020.
“Despite this, the population is still only a fraction of historical levels but catch per unit effort data—a standard measure of relative abundance— for the skate has ceased to decline overall since 2021,” said IMAS researcher and Maugean Skate captive breeding program leader, Professor Jayson Semmens. Maugean skate hatchlings take about six years to mature, so we will not see immediate recovery of adult biomass, but the return of juveniles to a proportion relative to adults in the sampling as we saw in 2014 is promising. There are far fewer juvenile carp this year and continued monitoring will be very helpful to determine whether or not the species control efforts will have any long-term benefit.
Cautious Optimism
The news of the juvenile Maugean skates is a positive development, but other populations are still in trouble and it’s too soon to be sure they will rebound.
IMAS researcher Dr. David Moreno said: “More information is needed before we can be sure that the presence of juvenile skates bound for a recovery (is) obtained.” “Current population models and management actions will come under question if preventative maintenance is not undertaken to ensure the species survival in Macquarie Harbour, its only remaining habitat.”
Together with the expanded dataset and indication of population stasis, this highlights the importance of continued support and monitoring which will be essential in directing successful conservation action for Maugean skate.
IMAS Fisheries and Aquaculture Centre Head Professor Sean Tracey said: “This is science in action.” To date, all of the work has been based on the latest information available at that moment. The results have been funded through support from the Tasmanian and Australian governments to improve our knowledge of the Maugean skate. And as we continue to learn more, our role is to hopefully be updating and revaluating that information so decisions are being made based on the best data we can have at this period of time.”
Conclusion
A rare ray gives birth and a crocodile infrastructure brings the opportunity to breathe again for endangered fish found smack bang in Renaissance man’s influence fortress, but scientists suspect their lifeline maybe terminal. Monitoring and further research is essential to inform meaningful conservation measures that save this unique ray from disappearing from its last refuge.
